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PHILADELPHIA (CBS) – Fifteen-year-old Trevonte Marks — a sophomore at Charter High School for Architecture and Design — was gunned down on the 1200 block of South 15th Street in the Point Breeze section of South Philadelphia Thursday night, just one block from his home.

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“My daughter called me hollering and screaming and that she was at the hospital and that they killed my grandson,” Marks’ grandmother Monique Oberleton said.

Oberleton says Marks was walking home after playing basketball with friends Thursday evening when he was shot. She believes he was not the intended target.

“Honor roll, basketball, real family-oriented and he loved his siblings,” she said of Marks. “He did everything he could for his mother. Not a problem child kid at all.”

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Investigators say Marks was with a 16-year-old boy and a 20-year-old man. Both were shot and are expected to survive.

Police are searching for at least three suspects; all males who they believed jumped out of a vehicle and fired shots.

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“We were told a 41-round fire during the course of this shooting,” Philadelphia Police Department Lieutenant Norman Davenport said.

Police Commissioner Richard Ross says something has to change.

“We’ve got to do something to change the mindset to get these young men in particular to understand you know how precious life is,” Ross said. “That’s what’s they’re not getting and that’s what saddens us.”

It’s a feeling Marks’ family knows all too well.

“My heart is heavy,” Oberleton said. “I’m here with the family. My daughter, his brothers and sisters.”

Police were able to get some surveillance video in the area. The motive of the shooting is still unclear.

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Anyone with any information is asked to call police at 215-686-TIPS.